1. Field of the Invention
The invention relates to hermetic biocompatible packaging and more particularly to packaging that is deposited in successive layers over three-dimensional structures.
2. Description of the Related Art
Packaging which is cost-effective and compatible with miniaturization is an important factor in the production of an implantable medical device. There is a need for a reliable, cost-effective batch-manufacturing packaging process such as a wafer level packaging, to protect components such as electronic- and mechanical components, micro-electronic- and mechanical systems, micro-electro-mechanical systems and substrates carrying such components. Such packaging must be mechanically and chemically stable to protect the body tissue from potentially toxic dissolvents, and also to protect the components of the implanted device from corrosion or degradation created by bodily fluids.
Encapsulation of organic light emitting diodes by at least one barrier stack is disclosed in U.S. Pat. No. 6,570,325 by Graff et al. The barrier stack includes at least one barrier layer and at least one decoupling layer. Other protective barriers which include parylene for opto-electronic devices are disclosed by Lee et al. in U.S. Patent Application Publication Nos. 2005/0146267, now U.S. Pat. Nos. 7,364,925, and 2007/0216300, now abandoned.
Techniques for protecting integrated circuits using copolymers formed of parylene N and co-monomers with various double bonds is disclosed by Lang et al. in U.S. Pat. No. 6,709,715. Other, more recent coating techniques utilizing parylene are disclosed by Bedinger et al. in U.S. Patent Application Publication No. 2009/0291200 and by Martin, III et al. in U.S. Patent Application Publication Nos. 2009/0263581 and 2009/0263641.
It is therefore desirable to provide improved hermetic biocompatible packaging, especially for implantable medical devices for which reduction of size is preferred.